An alpha-D-galactosyltransferase activity in Ehrlich ascites tumor cells. Biosynthesis and characterization of a trisaccharide (alpha-D-galactose-(1 goes to 3)-N-acetyllactosamine).
An alpha-D-galactosyltransferase activity has been detected in membranous fractions (42,000 x g) of Ehrlich ascites cells which transfers galactosyl groups from UDP-galactose to endogenous and exogenous acceptors. The products of the reaction contain alpha-D-galactopyranosyl groups at the nonreducing termini. A solid state assay was developed to follow alpha-D-galactosyltransferase activity in the presence of beta-D-galactosyltransferase. Examination of a variety of insolubilized exogenous acceptors indicated that the most active acceptors for the alpha-D-galactosyltransferase had the structure beta-D-Gal-(1 goes to 4)-beta-D-GlcNAc(1 goes to at their nonreducing termini. Incubation of UDP-[14C]galactose and beta-D-gal-(1 goes to 4)-D-GlcNAc (N-acetyllactosamine) or of UDP-galactose and beta-D-[14C]Gal-(1 goes to 4)-D-GlcNAc in the presence of the alpha-D-galactosyltransferase resulted in the enzymic synthesis of a 14C-labeled trisaccharide. Chemical and enzymic methods of analysis revealed the structure of the trisaccharide to be alpha-D-Gal-(1 goes to 3)-beta-D-Gal-(1 goes to 4)-D-GlcNAc. These data indicate that the alpha-D-galactosyltransferase in Ehrlich ascites cells transfers galactosyl groups to suitable acceptors to form an alpha-(1 goes to 3)-D-galactosidic linkage.
D000818:Animals; D002236:Carbohydrate Conformation; D002286:Carcinoma, Ehrlich Tumor / Q000201:enzymology*; D002462:Cell Membrane / Q000201:enzymology; D005700:Galactosyltransferases / Q000378:metabolism*; D051379:Mice; D009844:Oligosaccharides / Q000096:biosynthesis*; D013379:Substrate Specificity; D014312:Trisaccharides / Q000096:biosynthesis*; D014531:Uridine Diphosphate Galactose
D009844:Oligosaccharides; D014312:Trisaccharides; D014531:Uridine Diphosphate Galactose; C030329:alpha-galactose-(1-3)-N-acetyllactosamine; D005700:Galactosyltransferases